With rapid progresses of communication and semiconductor technology development, wireless sensor networks are used in the biomedical information field and related applications. Rather than interacting directly with a patient to obtain a diagnosis, doctors can use wireless sensors and the IBC technology, coupled with electrical devices for detecting and analyzing patients' physiological conditions. There are three methodologies to implement IBC technology, and one of them uses a patient's body and a conducting wire. The patient's body is used as a conductor. The conducting wire serves as a grounding conductor to form a circuit loop. The other way uses an electrostatic coupling method proposed by Zimmerman and does not employ a conducting wire. However, transfer efficiency is easily affected by the environment, and the transmission speed is slow. Another way uses a guided wave to transmit information and the communication quality is less influenced by environmental factors.
In 2003, Hachisuka et al. reported a FM/ASK hybrid transceiver with a carrier frequency of 10 MHz. However, the device is suffered from low data rate, which was about 9.6 kbps, and low integration level (Development and performance analysis of an Intra-body communication device. The 12th Int. Conference on Solid state sensors Actuators, and Microsystem. 1722-1725. June 2003).
Shinagawa et al. proposed a high data rate (10 Mbps) near-field sensing hybrid transceiver for IBC based on the electro-optic effect in 2004. However, it had drawbacks of low integration rate, high power consumption and large form factor (A near-field-sensing hybrid transceiver for IBC based on the electro-optic effect. IEEE trans. on instrumentation and measurement. 53(6): 1533-1538).
Drawbacks with lower integration level and slow data rate in the foregoing communication devices result in difficulty in real applications. Therefore, it is important to construct a small, light and minimized IBC device as a SOC.